Shells and algae, such as blue mussel (Mytilus edulis), barnacle (Balanus sp.), oyster, Hydrozoa, hydra (Hydra sp.), serpula (Serpula sp.), ascidian, bryozoan, pond snail, sea lettuce (Ulva sp.), Enteromorpha sp., and Ectocarpus sp. are adhered and grown on portions which always contact sea water or fresh water, such as fishing nets, bottoms of ships, marine equipment such as buoys, marine constructions, thermal or atomic power plants, inlet channels for cooling water in various fields of industries, underwater constructions, such as equipment attached to a dam, and reservoirs.
If those aquatic organisms are adhered to breeding nets, openings of nets are clogged. As a result, growth of breeding fishes is inhibited with decrease of circulation of sea water, resulting in many occurrence of fish diseases.
The adhesion of those aquatic organisms to ships causes increase of fluid resistance, resulting in decrease of navigation speed, increase of fuels consumed, loss of cost for cleaning ship bottoms and cost due to suspension of the service, and the like.
In marine equipment, and marine and underwater constructions, the adhesion of aquatic organisms invites weight increase and considerable disadvantage in handling operation. The adhesion to inlet channels causes decrease of thermal conductivity, and also causes the problems that inlet channels are clogged, and the amount of water intaken is decreased.
Conventionally, in order to prevent the adhesion and propagation of marine and fresh water aquatics, antifouling coating comprising organic tin compounds such as bis(tributyltin) oxide, or copper compounds such as copper sulfate or cuprous oxide have been used
Further, with respect to isocyanuric acid compounds which are the active ingredient in the present invention, use as a composition for exterminating harmful insects to woody materials (agents for exterminating termites) is disclosed in Japanese Patent Application Laid-open No. Sho 54-147924, use as a soil treating agent for ant proof is disclosed in Japanese Patent Application Laid-open No. Sho 64-3, use as ant-proof power wires is disclosed in Japanese Patent Application Laid-open No. Hei 2-78110, and use as a repellent for phlebotomic insects (repellent for mosquitoes) is disclosed in Japanese Patent Application Laid-open No. Hei 4-164003.
Though being effective in preventing the adhesion of aquatics, the above-mentioned organic tin compounds are highly toxic, and are especially prone to accumulate in the bodies of fishes and shellfishes. For the sake of promoting the environmental pollution, the use of those compounds is now under legal controls.
For example, in the United States of America, use of organic tin ship paints is inhibited to ships of 65 feet or less by the Organic Tin Antifouling Paint Regulation (1987). In the United Kingdom, use of tributyltin-containing antifouling agents to ships of 25 m or less and marine agriculture is inhibited by the Food and Environment Protection Law (1987).
Further, in Japan, tributyltin oxide is designated as a first-class specific chemical substance, and triphenyltin compounds and tributyltin compounds are specified as a second-class chemical substances, according to the Chemical Substance Examination Rule (Kashinhow) (1990). Use of those compounds are inhibited to fishing nets.
Furthermore, it is also taken a measure of inhibition of the use of tributyltin types for ship bottom coatings (Notification by the Ministry of Transportation, 1990).
The above-mentioned copper compounds are widely used as antifouling coatings for inlet channels and ship bottoms. However, since such copper compounds contain heavy metals similar to tin compounds, the use thereof is anxious for environmental pollution in future. Therefore, it cannot be said that such compounds are preferable agents for preventing the adhesion of aquatic organisms.
Further, the above-mentioned Japanese Patent Application Laid-opens No. Sho 54-147924, No. Sho 64-3, No. Hei 2-78110 and No. Hei 4-164003 do not disclose that the isocyanuric acid compounds as the active ingredient in the present invention is effective as agents for preventing the adhesion of aquatic organisms.